The oxidizing agents contained in bleaching agents are able to lighten the hair fibers by the oxidative destruction of the hair's dye melanin. For a moderate bleaching effect, the use of hydrogen peroxide, if necessary using ammonia or other alkalizing agents, is sufficient as oxidizing agent alone; for the achievement of a stronger bleaching effect, a mixture of hydrogen peroxide and peroxodisulfate salts and/or peroxomonosulfate salts is usually used.
However, aqueous hydrogen peroxide solutions are unstable at the alkaline Ph values required for the application, so that commercially available oxidative dyeing and bleaching products generally consist of at least two components. The first component is an acid-adjusted oxidizing agent preparation with hydrogen peroxide, which is mixed with an alkaline-adjusted second component shortly before use. For reasons of stability, commercially available bleaching agents are therefore usually offered in two preparations which are packaged separately from one another, which are mixed into a ready-to-use application immediately before use. Usually, commercially available bleaching agents consist of a liquid oxidizing agent preparation and a powder which contains solid oxidizing agents. Since these powders are often offered in doses, however, there is the danger of overdosing.
WO 03/089330 A1 discloses a permanent hair dyeing composition in which the dyeing ingredients, developers and oxidizing agents are contained in a flexible two-chamber container which allows the two dyeing components to be pressed out with the fingers. DE 4436863 C1 describes a two-chamber container for hair coloring agents, which allows dosing of the dyeing components by employing a mechanical closure system. The containers described in these printed documents have the disadvantage in that there is then a remaining container which has to be disposed of. Furthermore, the use of hydrogen peroxide as an oxidizing agent is described in both printed documents, which can lead to irritation, or even triggering allergies in extreme cases, with improper handling of a liquid component, for example by contact with skin parts or eyes.
WO 2016/074854 A1 discloses a cosmetic agent for whitening keratin fibers in which one of the components is packaged in a water-soluble film and the other component is again an aqueous oxidizing agent solution.